The present invention relates to tape cassettes for recording and/or reproducing apparatuses such as a video tape recorder (VTR), and in particular to miniature type tape cassettes which are smaller than standard type tape cassettes and the miniature tape cassettes are used together with a tape cassette adapter for standard type recording and/or reproducing apparatuses primarily designed for standard type tape cassettes. The present invention more particularly relates to miniature type tape cassettes into which there is built a lid locking mechanism for locking a lid which closes to protect a tape extending along the front of a cassette case.
As well known, tape cassettes of a standard type size are generally used in recording and/or reproducing apparatuses such as a video tape recorder (VTR). It is also well known that miniature type tape cassettes were recently developed which have the interchangeability with respect to apparatuses primarily designed for standard type tape cassettes and can be recorded and/or reproduced thereby.
This kind of miniature type tape cassettes can be recorded and/or reproduced not only by recording and/or reproducing apparatuses designed exclusively for the miniature type tape cassette, but also by a recording and/or reproducing apparatus primarily designed for the standard type tape cassette by being accommodated within a tape cassette adapter which is substantially the same size as standard type tape cassettes.
Also, the miniature type tape cassette is generally provided with a lid which closes to protect a magnetic tape extending along the front of a cassette case when the tape cassette is not used, and opens to a position not to interfere with the drawing of the tape out from the cassette case before the tape cassette is operated, wherein the lid is constructed to be maintained at either the closed state or the open state. Such a lid provided in the miniature type tape cassette is disclosed in the U.S. Pat. No. 4,494,161, for example, in which the assignee is the same as that of the present application.
However, conventional miniature type tape cassettes themselves do not have a lid locking mechanism for positively locking the lid which is intended to prevent the lid manually opened when the tape cassette is not loaded into a recording and/or reproducing apparatus designed exclusively for the miniature type tape cassette tape or into the tape cassette adapter. Therefore, the lid is easily rotated to its completely opened state against the elastic force provided by a leaf spring which urges the lid to fully opened or closed position with a locking motion. As a result, a signal recording surface of the magnetic tape can be exposed and dust or the like is liable to be deposited thereon. This may eventually damage or degrade the magnetic tape accommodated into the tape cassette and may therefore prevent stable recording and/or reproduction.
In order to eliminate the above problems, it is conceivable to provide a positive lid locking mechanism which has already been employed in the standard type tape cassette to the miniature type tape cassette. Such a positive lid locking mechanism includes a member for releasing the lock which is driven by a lock releasing mechanism provided in the recording and/or reproducing apparatuses for the standard type tape cassettes. However, these measures are not practical, as it becomes necessary to modify each of the adapters and the current recording and/or reproducing apparatuses designed exclusively for miniature type tape cassettes already marketed and operated at millions of homes to have corresponding lock releasing mechanism. In other words, it is impossible to adapt the miniature type tape cassette to have lid locking mechanism as described above for the current apparatuses which lacks the corresponding lock releasing mechanism, and to thus maintain the interchangeability. Furthermore, these measures would make the mechanism of the recording and/or reproducing apparatuses or the tape cassette adapters complicated. Of course, this would result in an increase in the total number of components.